Views: 0 Author: Site Editor Publish Time: 2023-08-09 Origin: Site
In recent years, with a large amount of waste directly or indirectly discharged into the soil, soil pollution has become increasingly serious, which has to arouse our great attention. Surfactant is a kind of material that can clean and repair polluted soil. It has good hydrophilicity, lipophilicity and special adsorbability. Its remediation of contaminated soil is mainly through increasing the solubility of organic pollutants, so that the pollutants in the soil are desorbed, and then achieve the purpose of soil remediation, and has good application effects in the remediation of organic matter and heavy metal pollution.
According to the contact between the surfactant and the pollutant, the solubilization process can be divided into the following two types: (1) direct solubilization, the monomer in the surfactant first contacts with the molecules in the pollutant, adsorbed the pollutant, and then formed micelles. The micelles spread continuously in the eluent and carry contaminants out of the soil. (2) Indirect solubilization, the surfactant first forms micelles, and then obtains pollutants through the aqueous medium and makes them enter the core of the micelle. In the process of remediation of contaminated soil, the selection of surfactants is an important link, which must fully consider the complexity of soil environment and the comprehensive solubilization effect of various forces of surfactants and pollutants.
At present, the application of surfactants in the remediation of contaminated soil is mainly in the remediation of organic and heavy metal contaminated soil.
Surfactants can be used for in-situ and ectopic remediation of soil contaminated by organic matter. Ectopic remediation mainly refers to the excavation of contaminated soil into a non-permeable container, and then the use of surfactants to remove organic pollutants in the soil, and the contaminated liquid is continuously discharged from the soil. In-situ remediation is carried out by spraying the surface of contaminated areas and pumping Wells. The surface active extractant is first sprayed on the surface of the contaminated soil. The extractant will percolate in the soil and transfer the contaminant to the contaminated groundwater in the seepage zone. The contaminated water is then extracted and treated accordingly in the extraction well.
In the remediation of soil contaminated by heavy metals, anionic surfactants adsorbed on the surface of soil particles and then complexed with heavy metals to dissolve heavy metals in soil solution. Cationic surfactants are mainly through the exchange of ions themselves to gradually transfer the cations in the soil to the liquid phase, to achieve the purpose of soil repair; Nonionic surfactants have relatively low efficiency in removing heavy metals from soil because of their direct complexation with heavy metals.